The present invention relates to tools for resurfacing a counter-bored top of a cylinder bore of an engine block, such as in a diesel engine.
Brooks U.S. Pat. No. 3,350,964 discloses a counterbore facing tool where the operator manually rotates the tool while pressing downward. A problem is that it is difficult to provide a balanced, centered and constant downward force while rotating the tool's cutter in a manner that prevents chatter and/or other surface imperfections during the rotation. Notably, the Brooks' tool is re-gripped about every 180 degrees of rotation, and the instructions for this tool state that the operator should NOT stop rotation in the same handle position (as the operator stops and regrips the T-shaped handle of the device) to avoid creating a ridge in the counterbore. Another problem is that a depth of the tool is controlled by rotation of a threaded nut (see nut 31 in U.S. Pat. No. 3,350,964), and thumb set screw (34), which requires partial depth adjustment of the nut after each rotation of the handle. This is inconvenient, time consuming, and can cause operators to be over-aggressive in the stepped adjustment so that they can finish the machining operation with fewer rotations of the tool . . . thus resulting in worse surface imperfections in the counterbore.